You can do this using IP Webcam android application.

Steps -

1. Install the application in your android phone.
2. Connect your Laptop and Phone in a local network (you can use mobile hotspot).
3. Start application and select Start Server option, the application will start capturing video and show you IP addresses.
4. Use this IP address to read the video feed using the following python code.
5. Process the video using OpenCV.

Python code -

import urllib
import cv2
import numpy as np
import ssl

ctx = ssl.create_default_context()
ctx.check_hostname = False
ctx.verify_mode = ssl.CERT_NONE

url = 'Your URL'

while True:
    imgResp = urllib3.urlopen(url)
    imgNp = np.array(bytearray(imgResp.read()), dtype=np.uint8)
    img = cv2.imdecode(imgNp, -1)
    cv2.imshow('temp',cv2.resize(img,(600,400)))
    q = cv2.waitKey(1)
    if q == ord("q"):
        break;

cv2.destroyAllWindows()

You can find the android application here - IP Webcam

And this video will explain better - How to use with OpenCV